Evangelist Billy Graham is keeping a positive attitude during his hospitalization for respiratory problems.

A. Larry Ross, a spokesman for the 93-year-old evangelist, tweeted early this morning that Graham "remains in good spirits after a time of Bible reading and prayer with daughter, Gigi, last nite."

Graham currently remains at Mission Hospital in Asheville, N.C., where he was admitted late Wednesday morning "suffering from congestion, a cough and a slight fever," according to AP. He is being tested for pneumonia, which he was previously treated for in May.

The hospital said that he was "alert, smiling and waving at hospital staff" when he was admitted and that "while no date has been set for discharge, Mr. Graham is looking forward to returning home to spend the upcoming Christmas holidays with his family."

Many Christians took to Twitter to express their well wishes.

"Praying for Dr. Billy Graham, taken into hospital in Asheville, NC for evaluation and lung treatment," tweeted Sheila Walsh. "What a hero of the faith."

Founding pastor of the Fellowship Church Ed Young tweeted, "Praying for Billy Graham as he's in the hospital. One of the greatest men God has used to reach millions! Get well, Dr, Graham!!"

Graham is one of the most renowned Christian preachers of the century who, according to the Cincinnati Post, has personally preached the Gospel to more people than anyone else in history. Graham rose to fame during the post-World War II period during which he spoke out against communism and helped unite the country by bringing Christianity back to the forefront. He is most well-known for his heartfelt and compelling sermons.

Graham's 30th book, Nearing Home: Life, Faith, and Finishing Well, in which he shares personal reflections and wisdom on growing old, was released in October.

"All my life I was taught how to die as a Christian, but no one ever taught me how I ought to live in my latter years," the greatly admired evangelist wrote. "I wanted to share some of the things I have learned about this stage in life with others, as the aging process is something most of us will experience."